As recording media on which various kinds of data are recorded, optical discs such as digital versatile discs (DVDs) or Blu-ray (registered trademark) discs (BDs) are used often.
In general optical discs, lands (ridge portions) and grooves (valley portions) are formed. With the land and groove configuration, a tracking process of specifying a track position even in a data-unrecorded state can be performed.
In general discs of the past, a data recording process was performed only on grooves and data recording was not performed on lands on either side of the grooves.
A configuration of an optical disc that has lands and grooves and an example of a data recording process are disclosed in, for example, Patent Literature 1 (JP 2015-1998A).
In recent years, as a scheme of further improving a data recording density to increase a data recording capacity, a land and groove recording scheme of recording data not only on grooves but also on lands has been proposed.
By performing data recording on both lands and grooves in this way, it is possible to almost double an amount of data which can be recorded on one disc.
However, when the land and groove recording scheme is applied, data recording errors occur in certain conditions.
Specifically, for example, when data recording is attempted on certain grooves, the data recording is not correctly performed on the grooves and a recording error may occur when one of the lands on either side of the grooves is a land on which the data recording is finished and the other land is a data unrecorded land.
One cause for such recording errors is considered to be that a minute difference occurs in reflected light from lands on both sides of a groove of a data recording region and tracking is not accurately performed.